The invention relates to a method for driving off and collecting propellants, e.g. chlorofluoro-carbons (CFCs) from foam materials, e.g. insulating foam in refrigerators, freezers, district heating tubes, etc, which method involves the use of a closed container in which a mechanical decomposition of the product is effected.
By other prior art techniques it is only possible to destroy these foam products in such a manner that the propellants are liberated and either escape into the atmosphere thus charging the environment and/or are being decomposed to highly poisonous products.
From DE-A-3,830,118 a method is described by which the liberation of the propellants is effected in a closed chamber defined by a cylinder and two pistons. However, such chamber would be inconvenient as it is difficult to provide sealings by which any escape of propellants into the atmosphere is obviated.
It is the object of the invention to remedy the above drawbacks and to provide an environmentally friendly method for driving off and collecting propellants, e.g. CFCs from foam material. This object is achieved with a method being characterized in that the mechanical decomposition of the product and the liberation of the propellant is effected inside a cup-shaped process container having the closed part of the cup turned upwardly and the open part of the cup placed below the surface of a liquid medium, e.g. water, under/in which liquid medium the decomposition and liberation is effected.
If foam products are decomposed mechanically (crushed) without being surrounded by a liquid medium it is difficult to condense the propellants sufficiently as the propellant gases are mixed with large amounts of air which impedes an efficient condensing of the propellants.
Accordingly, these materials are being deposited for being removed/destroyed at a later time when a suitable method has been developed.